Roller path compensator



Sept. 11, 1956 wo 2,762,266

ROLLER PATH COMPENSATOR Filed July 16, 1952 Y l 6 75 74 swvcHeo 5 SUN GEAR/N6 LEVAT'NG I MECHANISM su/v owe-ewe I I I l l I l ELEVATION 02052 E i 23\ AMPLIOYNE 24 l AMPLIFIER GENEEATOE V E ELEVATION I ORDER I I TEA/N 020:2

INVENTOR. 41 FEED A. WOLF United States Patent C ROLLER PATH COMPENSATOR Alfred Adams Wolf, Dallastown, Pa.

Application July 16, 1952, Serial No. 299,321

3 Claims. (Cl. 89-41) (Granted under Title 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

This device generally relates to a gun elevating system, and more particularly to a gun elevating system compensating for the roller path error of a gun turret relative to the true horizon.

In the art of remotely elevating guns, the command signal generated at a remote control station generally corresponds to the desired elevation of the gun with respect to a fixed reference plane such as the horizon. However the gun itself located at a distance therefrom and controlled by this command signal is generally afiixed within a turret and therefore may have its angle of elevation referenced to the plane of this turret and not the horizon. Should the turret be positioned in a plane parallel to the horizon, the gun is always accurately positioned by the command signal to the desired angle with respect to the horizon; however if the turret does not lie in a truly horizontal plane, the angle of elevation assumed by the gun in response to the remotely generated signal is in error by an amount attributable to the inclination of the turret with respect to the horizon. It has been generally found to be extremely difficult to precisely align a gun turret parallel to the horizon, and accordingly suitable means have long been sought to compensate for the error arising therefrom.

In instances where the gun is remotely positioned in elevation, and in addition remotely positioned in azimuth, the problem becomes more difiicult for the turret is generally mounted on rollers, and therefore should the plane of the turret roller path be inclined with respect to the horizon, rotation of the turret introduces an elevational error whose value differs for each angle of train. This variable elevation error with train is termed in the art the roller path error.

The present device to compensate for this roller path error provides a servo system for accurately positioning a gun in elevation in response to remotely generated command signals by employing a means for inserting an electricial correction signal in the system which is always equal and opposite to the roller path error for any angle of train, whereby the gun is always elevated from the turret by an angle which when added to the roller path error angle equals the desired gun elevation angle with respect to the horizon.

It is accordingly one object of this invention to provide a servo system for accurately positioning a gun in elevation at any given train angle, despite roller path errors.

A further object of this invention is to provide a servo for accurately positioning a gun in elevation, and compensating for the inclination of the gun turret roller path relative to the true horizon.

A further object of this invention is to provide a servo for positioning a trainable gun in elevation and electrically compensating for the inclination of the gun turret roller path relative to the true horizon.

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Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. 1 is an exaggerated schematic presentation of a gun and inclined gun turret, and illustrating the gun turret roller path errors; and

Fig. 2 is a schematic presentation of a gun elevating servo system, constituting one preferred embodiment of the present invention, having electrical compensating means for the gun turret roller path error.

Referring now in detail to the exaggerated sketch Fig. 1, a gun 5 movable in elevation is affixed within a gun turret 6 rotatable with respect to a fixed support (not shown) which may comprise the deck of a ship or a portion of land. Turret 6 is mounted on rollers (not shown) operating in plane 7, illustrated as a perspectively represented circle, which is tilted with respect to a plane 8 lying parallel to the actual turret support. Assuming plane 8 lies parallel with the horizon, it may be observed that the elevational angle of the gun with respect to the horizon, in the right hand position shown, is equal to the sum of the turret inclination angle a1, plus the elevation of the gun with respect to the turret angle 31, and therefore if the gun is to be directed to an elevation angle of 'y with respect to the horizon, the gun must be elevated to an angle [31 from its turret, this angle constituting the difference between the desired angle 'y and the turret inclination angle mi. The turret inclination angle on is obviously a constant for all angles of elevation at any particular azimuth position. However, as in most instances it is desired that the gun also be adjustable in train, the problem becomes more difiicult, for although the plane of rotation 7 of the turret remains at a fixed inclination with respect to the support or plane 8, the elevation inclination error of the gun or turret varies as the turret is rotated, from a maximum tilt with respect to the horizon in one direction, through zero, to a maximum tilt in the opposite direction. This variable tilt or roller path error with train is represented in Fig. l by the length and direction of arrowed lines 9 positioned intermediate the periphery of the rotatable plane 7 of turret 6 and a circular outline 10 located in plane 8 parallel to the plane of the support. Thus, for example, as the gun is trained to the second or left hand position shown, its roller path error angle 012 due to the turret inclination is in the opposite direction from that of :11, whereby gun 5 must now be elevated from the turret to an angle B2 greater than B1, if the gun is to be positioned in elevation to the same angle 7 with respect to the horizon as in the first position. Thus the angle of gun elevation with respect to the turret 82 is determined by subtracting from the desired angle of elevation from horizon 'y the negative angle of turret tilt 0:2.

It has been determined and may be shown that for any given turret inclination with respect to the horizon or other reference plane employed by the gun director, the roller path error attributable to this tilt as the gun and turret are trained in azimuth varies between a maximum positive value and a maximum negative value directly as the sine of the angle of train. Therefore, in the elevation servo system constituting a preferred embodiment of the present invention to be subsequently described, the gun is automatically directed in elevation and its position automatically compensated for the roller path error by adding a correction signal proportional to the sine of the azimuth train angle.

The correct angle of elevation of the gun with respect to the turret is effected in substance by subtracting from the elevation command signal of the director, which represents a gun elevation referenced to a plane such as true horizon or that upon which the turret is mounted, the algebraic quantity of the roller path error for the particular angle of train which the gun occupies, in accordance with the formula fi='y--a, wherein u is the angle of elevation of the gun with respect to the azimuth plane of the turret, 'y is the angle of elevation required by the director with respect to its reference plane, and a is the roller path error for the particular azimuth angle, which varies between a maximum positive and maximum negative quantity as the gun and mount are trained in azimuth.

Referring to the partial schematic diagram of Fig. 2 for illustrating one embodiment of a servo system constructed in accordance with the present invention for directing a gun in elevation and compensating for the turret roller path error, the circuits within dotted enclosure designated 11 comprise the components of the elevation servo system positioned adjacent the gun and gun turret, and those without dotted enclosure 11 constitute the remaining elements of the servo system positioned at a distance therefrom, such as at an observation and remote control station. Within enclosure 11, servo amplifier 12 receives a command signal directing a given elevation of the gun. This signal is then voltage amplilied and conveyed to a power amplifying amplidyne generator 13, as illustrated by the arrows, where sufiicient power is controlled to energize the gun elevating motors and mechanism 14, enabling the elevation of the gun to an angle determined by the command signal. To complete the position servo loop, elevation of the gun from the ,turret rotates shaft 15 and thereafter shaft 17 through suitable gearing 16, enabling shaft 17 to control the input to amplifier 12 and thereby diminish the command signal as the gun reaches the proper elevation.

The command signal energizing servo amplifier 12 comprises a resultant signal derived from three sources, a

coarse elevation selsyn receiver 18, a fine elevation selsyn receiver 19, and a roller path error compensating autotransformer 20. As may be observed from Fig. 2, the

rotor of coarse elevation selsyn 18 in series with the output of the roller path error autotransformer output 2t) energizes two terminals of servo amplifier 12, and the rotor of fine elevation selsyn 19 in series with the roller error autotransformer 20, stepped down through a transformer 21, energizes the remaining two terminals of servo amplifier 12.

Without dotted enclosure 11, a gun director 22, usually located at a distance from the gun, initially ascertains the elevation and azimuth position from the horizon of a selected target by radar or other suitable means, and thereafter converts this electrical intelligence to mechanical rotation of two shafts 23 and 24. Shaft 23, comprising the elevation command output of gun director 22, is connected to the rotors of coarse and fine selsyn transmitters 25 and 26 through suitable gearing means, which transmitters operate to convert the mechanical signals to coarse and fine electrical command signals suitable for transmission to the remotely located coarse and fine selsyn receivers 18 and 19. Shaft 24, comprising the train command output of gun director 22, is connected to energize circuits for transmission of train signals to a remotely controlled gun train positioning servo (not shown) and in addition is connected to rotate the rotor of roller path error selsyn transmitter 27. This latter signal is directed to the stator of a selsyn receiver 30, having an adjustable means 28 and 29 for positioning its rotor, and which is electrically connected to energize autotransformer 20.

Considering the overall operation of the system of Fig. 2, elevation commands from gun director 22, corresponding to the desired elevation of the gun with respect to the horizon, are transformed to electrical signals and conveyed to the remotely located servo amplifier 12 by means of the coarse and fine selsyn transmitters and receivers, 25, 26, 18, and 19. Concurrently, train commands from gun director 22, are transformed to elecroller path error.

the instant servo system to compensate for the roller path error of the turret of a particular gun installation, the turret is rotated by the director 22 to a gun train position having a maximum tilt error, and the rotor of selsyn train receiver 30 is thereafter positioned by means of adjusting means 28 and 29 to produce its maximum signal at this angle. Training of the gun by the director to any azimuth angle on either side of this maximum tilt angle, then results in a lesser voltage from selsyn 30, proportional to the sine of that angle, being conveyed to auto-- transformer 20. Autotransformer 20 is also adjusted at this maximum tilt angle to select the magnitude of voltage compensation applied to servo amplifier 12, wherebythe correction voltage applied is equal and opposite to the Thus the input to servo amplifier 12 for any train angle comprises voltages proportional to the desired elevation of the gun with respect to the horizon, minus a voltage proportional to the tilt of the gun caused by the roller path error, thereby enabling the servo positioning system to elevate the gun from the turret by an angle which when added to the roller path inclination accurately equals the desired elevation with respect to horizon.

Throughout the above description, it has been assumed for purposes of simplicity that the turret fixed support (not shown) and plane 8 parallel thereto lie parallel to the elevation reference plane of director, whereby correcting the gun for true elevation with respect to the support corrects the gun for the actual director required elevation. However, in the event the surface of the fixed support is not parallel to thatof the director reference,- the above apparatus may still be successfully employed by directly determining the turret inclination with respect thereto and adjusting the compensating means accordingly, as is apparent to those skilled in the art.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A device for compensating roller path error in a gun elevating system comprising a turret, a gun movable in elevation and rotatably mounted on said turret, a gun director, a plurality of selsyn transmitters rotatably connected to said gun director for supplying electrical command signals proportional to the desired elevation of said gun, a roller path error selsyn transmitter rotatably connected to said gun director for supplying electrical command signals proportional to the sine of the angle of train, and an elevation servo system including a plurality of selsyn receivers, a servo amplifier, and an amplidyne generator for positioning said gun in elevation in response to the resultant signal derived from said transmitters.

2. A device for compensating roller path error in a gun elevating system comprising a turret, a gun movable in elevation and rotatably mounted on said turret, a gun director, a coarse and a fine elevation selsyn transmitter connected to said gun director for supplying electrical command signals proportional to the desired elevation of said gun, a roller path error selsyn transmitter rotatably connected to said gun director for supplying electrical command signals proportional to the sine of the angle of train, a plurality of selsyn receivers having output rotors, one each being adaptable to receive electrical signals from each said transmitter, a variable autotransformer connected to one of said receivers for adjusting the magnitude of said command signals, and an elevation servo system including a servo amplifier having more than one input, and an amplidyne generator for positioning said gun in elevation in response to the resultant signal derived from said plurality of selsyn receivers.

3. A device for compensating roller path error in a gun elevating system as set forth in claim 2 wherein a step-down transformer is connected to the autotransformer output and said autotransformer and one receiver output rotor are electrically connected in series to one amplifier input and said step-down transformer and another receiver output rotor are connected in series to a second amplifier input.

References Cited in the file of this patent UNITED STATES PATENTS Bates Oct. 27, Borden Jan. 28, Agins et a1 June 13, Harris Feb. 26, Ewing July 29, Hammond et al Mar. 22,

FOREIGN PATENTS Great Britain May 28, 

